Catching Rays

As spring quickly approaches and being outside is becoming more and more inviting, we Public Observatory staff continue to enjoy spending time outside with our portable telescopes. Every sunny day between 12:30 p.m. and 2 p.m., except for Mondays, we invite visitors near the Independence Avenue entrance to take a look at the sun through our specially equipped telescopes.

The Sun is approaching the active portion of its 11-year cycle, so visitors these days are now more likely to catch a glimpse of an interesting feature on the surface of the Sun. Many visitors have been able to observe dark sunspot groups in our white light telescope, or spy an interesting prominence in the sun’s atmosphere through the telescope equipped with a hydrogen alpha filter. However, the sunspots eventually move out of view and the prominences stop being quite so, well, prominent.

Luckily, there is a way to preserve these fleeting features so that all visitors will get a chance to see them regardless of how the sun chooses to behave that day. We have started taking pictures of the Sun’s interesting features through our different telescopes. Here are those images for your viewing pleasure!

Here is an image of the Sun that was taken right here at the Museum on February 18th. In order to capture this image, we used a camera attached to our hydrogen alpha telescope. This telescope reveals the Sun’s chromosphere, filtering out all light except the red light given off by excited hydrogen atoms. This image shows the two large prominences that appeared on the Sun that day. You can also see some surface texture on the Sun, which is called granulation. If you were to look through our hydrogen alpha telescope, this is pretty much exactly what you’d be able to see!

We took pictures later on in the day to see how the prominence changed, and could take pictures the next day as well. Over time, this loop prominence became twisted before disappearing from our view.

We took this picture of the Sun’s chromosphere with our Calcium-K telescope on March 4th. The Calcium K telescope filters out all but the purple light coming from excited Calcium atoms in the Sun’s atmosphere. You might notice a few brighter spots on the Sun’s surface, especially near the top right. These are hotter areas on the Sun called plages (pronounced like you’re saying “blah” except with a p).

We took this image of a super-prominence in the chromosphere of the Sun using our hydrogen-alpha telescope on March 17th. This prominence is truly gigantic; it’s about 5 earths tall 22 earths long!

While these pictures are pretty great, nothing quite compares to seeing the sun live through a telescope. It’s always exciting to see what the Sun is up to on any given day. We’re outside the Museum every sunny day except for Monday between 12:30 p.m. and 2 p.m., so stop by and catch a few rays!

Erin Braswell is an Astronomy Educator at the National Air and Space Museum